A liquid crystal display device using a display panel including a liquid crystal cell is used as a display of a television, a monitor or the like. However, the liquid crystal display device has a contrast ratio lower than an organic electro luminescence (EL) display device.
A technique, in which two display panels overlap each other and an image is displayed on each display panel, is conventionally proposed as a technique of improving a contrast ratio of a liquid crystal display device (for example, see Unexamined Japanese Patent Publication No. 2011-076107). A color image is displayed on a front-side (observer-side) display panel in two display panels disposed back and forth, and a black-and-white image is displayed on a rear-side (backlight-side) display panel, thereby improving the contrast ratio.
In this case, the two display panels are bonded together by a bonding layer such as an optically clear adhesive (OCA) and an optically clear resin (OCR).